Autologous chondrocyte implantation (ACI) is a clinically relevant treatment to repair articular cartilage in patients with knee cartilage defects. This repair method is based on the introduction of adult chondrogenic cells into the defect area. To accomplish this, chondrocytes are first isolated from a limited amount of articular cartilage harvested arthroscopically from a minor weight-bearing area of the injured knee of the same patient. The cells are released from the cartilage tissue by enzymatic digestions and expanded in culture medium until a sufficient number of cells are obtained to fill the focal cartilage defect. The most common sites for cartilage biopsy harvest recommended by orthopedic surgeons are the non-weight bearing areas of the superomedial or superolateral edge of the femoral condyle or the lateral and medial intercondylar notch. Today, an arthroscopic gouge or ring curette is used to obtain two or three small slivers of partial to full thickness cartilage. However, the harvested cartilage quantity is highly variable amongst surgeons due to device user characteristics.
The cartilage harvest procedure plays a crucial role in the process of cell cultivation, since sufficient starting material must be available to allow a successful manufacturing of the cells. On the other side, the biopsy amount taken must be restricted in order to minimize the lesion size created at the biopsy harvesting site. A controlled and consistent biopsy harvesting process is therefore highly desired.
Currently available biopsy devices are not designed to give consistent cartilage harvest material without contaminations by other tissues or the risk of loosing the biopsy during the procedure, or are restricted to only being used at specific sites (e.g. the notch).
One example of such a standard instrument is the Wiberg device as shown in FIG. 1. The device is a re-usable, stainless steel instrument with flat handle, long neck, and sharp-edged scoop at the end. The biopsy is taken by inserting the scoop into the cartilage, and then pushing and wiggling the instrument through the cartilage to obtain a biopsy piece. Biopsy quantities obtained with this instrument are extremely user dependent and lack standardization. Even with the same surgeon (user), a lack of consistent reproducibility has been observed despite long-term experience. Furthermore, the device is not user friendly since no control on the tissue depth and length is provided. In addition, it bears the risk of losing the biopsy during the arthroscopic procedure since the sample is not captured within the device. Consequently, one needs to use a slow, difficult “whittling” motion in order to obtain the cartilage sample.
Another example is the Storz instrument. The device uses a “punch” mechanism which punches out a small circular sample, comprising both a cartilage sample and part of an osteochondral layer. It is used at a perpendicular angle to the cartilage layer, punches through the entire layer, as well as the osteochondral layer—collecting the sample inside the instrument. This cartilage harvest device was specifically designed to obtain biopsies for the notch and can only be used at this location; and is used mainly in the German market. Only a small, limited amount of biopsy material can be harvested which often contains contaminating subchondral bone mass that is “punched out” together with the cartilage during sampling.
It is a particular object of the present invention to provide a biopsy device that addresses the aforementioned problems in that;                it is applicable to all locations within the knee joint (arthroscopic accessibility) with in particular the lateral and medial intercondylar notch;        it allows a controlled and consistent biopsy harvesting process;        it gives consistent cartilage harvest material without contaminations by other tissues or the risk of loosing the biopsy during the procedure.        
It is accordingly a general object of the invention to provide consistent biopsies, in width and height, without contamination by other tissues, that can be taken at all locations within the knee joint.